Voltage regulators, such as DC-to-DC voltage converters, are used to provide stable voltage sources for various electronic systems. Efficient DC-to-DC converters are particularly needed for battery management in low power devices (e.g., laptop notebooks, cellular phones, etc.). A switching voltage regulator generates an output voltage by converting an input DC voltage into a high frequency chopped voltage, and then filtering the high frequency chopped voltage to generate the output DC voltage. Specifically, the switching regulator includes a switch for alternately coupling and decoupling an input DC voltage source (e.g., a battery) to a load (e.g., an integrated circuit (IC)). An output filter, typically including an inductor and a capacitor, may be coupled between the chopped input voltage and the load to filter the output, and thus provide the output DC voltage. A controller (e.g., a pulse width modulator, a pulse frequency modulator, etc.) can control the switch to maintain a substantially constant output DC voltage.
Another type of converter is a linear regulator, which is suitable for converters having relatively low input to output voltage differences, as well as in low power applications where the input to output voltage difference is high. In a step down application where the input voltage is much greater than the output voltage, a switching regulator typically has better efficiency than a linear regulator due to substantial power loss in the linear regulator. However, switching regulators may incur power losses associated with the various switching actions (e.g., power device transitions, driving loss, etc.). In addition, switching regulator control is typically more complicated than that of a linear regulator, thus consuming more quiescent power. Consequently, switching regulator efficiency can suffer under relatively light output conditions, and may become lower than a corresponding linear regulator.